Duplex circuit.



L. ESPENSCHIED ADUPLEX omc-UIT." APPLICATION FILED OCT. I3. I9I5.

Patented July 17, v1917.

n @ya LL'D ESPENSCHIED, 0F BROOKLYN, NEW YORK, ASSIGNQR T0 AMERICAN TELEPHDNE AND TELEGRAPH CDMPANY, A CRIOItATION F NEW 'YDREL Dorn-nir CIRCUIT;

incarna To all fw/wm t may concern Be it known that l, LLOYD Esriinsoiimn, residing` at Brooklyn, in the county of Kings and State ol New York, have invented certain improvements in Duplex Circuits, of

` and phantom.-4

'the core. f

This invention has for its chief purpose the provision of device in which the fluir resulting fromcurrent in all `the duplex circuits will pass through common members of y Figure 1 ol? the accompanying drawings shows the invention diagrammatically in its application tofthe loading of a duplex telephone circuit; Fig 2 shows another embodiment ofthe invention; andFigs. 3 and l illustrate respectively' the vpaths followed by the flux due tothe side circuit and phantom l,

circuit currents inthe cores of the devices shown inflfigs. 1 and 2. The characters A,'B and C, D designate the line conductors oil'tWo ph sical televphone circuits' in. which thetalkmg current liovsin series through `looth pairs v0i' conducltors, asindicatedJ by full'and dashedarrows,

' conductors which respectively'. By any suitable means these physical circuitsare made to serve also vas a i phan toni circuit through which talking currentpasses in series loy'aiiray of the pairs of are joined in parallel, as thel dotted arrowsindicate. Included in the .duplex circuit .is an inductance device E 'adaptedto atleet all the three component` circuits, in the present instance togive a loading effect therein. This compound loading device or coil may comprise a `core conn sisting of end or head portions-10. and 11 oit magnetic4 material, thesebeing shown as toroidal,l though they may he in tlie.lorm of any closed gure and` the central openings may he' decreased in. diameter to any desired extent. The "toroids lie in parallel planes'with their .axes in alinement. Connecting the heads are.intermedieutev core 'porl tions, 'which in this embodiment .of the in-` vention may be considered as primaryineiw hers, Four-of these intermediate portions Specification of Letters Patent. Paten-$3@ July '1179 yglyly l pplication filed October 13, 1915. SerialNo. 455,717. i I

are illustrated, 12, `13, and l5, there being `one foreach line conductorofthe duplex circuit. Theyu are symmetrically 'arranged 90 apartabout the toroids and at right angles thereto. f

Each of the primary core portions carries awinding included in one or' the line conductors of the duplex ,'circuit, For con-- ductors A, B of one sidecircuit `windings La and Lb are mounted upon the` opposite intermediate portions l2 and 13, while the core portions 14E-,and l5 hear windings Lc and Ld for the conductors C, D of the other side circuit. Each pair of windings. L, L" and L, La are connected with their inductances mutually aiding; for current peculiar to the `side circuit: and 'therefore mutually opposing for phantom circuit current. The windings of din'erent side circuits are connected;

With their inductances mutually aiding fory phantom circuit current, In loading coils as now usually constructed, the windings helonging to `either side ciicuit are so `closely coupled inductively Ithat theypractically neutralize one anothers inductancesY in the circuit in which they `are joined .mutually opposing, :in the, present` case thephantom circuit. 'ln my invention,.however, the windings are loosely coupled ,by being on separate portions'lQ, 13, 14v and yll'ofthe `core and the quadrants of the toroids furnish. loranches ofthe core through which the phantom flux is diverted to the windings of the companion side circuit. Therefore, the phantom, as Well as the sides, is loaded. `This may be clearly seen in the fluir diagrams of Figs/3 and d. The iirst shows that the resultant flux for an instantaneous value of,y current in `the side circuit A, B through'the primary core portion 12 .flows :intotoroid `il] it `divides and .passes in opposite .directions to the portion 18, which it traverses to reach the toroid v and again divides `to return to the portionl. A similar distribution exists for the side circuit @,'D iwith respect to the Vother pair of primary `core portionslel and The Hur; of neither side circuit,will` link with the windings of the otherfsidecircuit so that there is nointerference. `For phantom cui-rentthe flux produced bye chdir links with the windings offtli ,othe

j-,without affecting the associated windings of the saine pair, .dividing inwoppositevdirec- `tions throughuthe ,toi-oid, quadrants lindsay,- ing,` `and returning to intermediate portions,

I phantom to side circuit inductance of approximatelyl.

as will be clear from Figi-,4. As allthe ftux due to any winding for either side or phantom current flows through the core portions 12, 13, 111 and 15 upon which the windings are placed, a minimum number of turns i The flux distribution just described may also be obtained by the application ofthe windings to the toroids;4 .Their quadrants,

using the terms previously applied to the core members, carrying inductance windings become the primary portions, while ,the

members 'intermediate'the toroids are the branch portions. But 1n this arrangement,

' .dueftothedivision o f .the flux through the toroids, .it is necessary to employdouble ,the number of turns of winding to produce l ,the same degree of-inductance. `As appears in -tlie device F of Fig.- 2, the windings of each side'cil'cuit are confined to one toroid,

Vthose for the conductors A, B being upon the toroidlO and those for conductors C, D being'applied to 11. Each line winding is preferably divided into two sections La` La; L", Lb; L, Lc; and L", Lf" situated upon adjacent toroid quadrants, and the Vwindings of eachline pair upon, one toroid lie at an angle of 9 0"` with respect to those of the' pair upon the other toroid. The twol vSections'for each conductor, as La, L, are

connected with their inductances mutually opposing, .and the` adjacent sections -of the different vwindings of the same side circuit, as La, L",'mutually aiding for side circuit current. Thus the two complete line windvings of each side circuit are connected in the other two.

'of each group mutuallyl aiding.

groups mutually opposing, with the halves The two side circuit windings are made mutually aiding for phantoin` circuit current by connecting sections upon corresponding quadrants of the two toroids mutually aiding. The ratio of phantom to side circuit inductance is as in the preceding form.

The mutual inductances'which affect the electromagnetic balance between the circuits are those between line windings of different side circuits. In order that the component circuits shall be balanced, and hence noninterfering in this respect, it is necessary that there be no resultant mutual inductanee betweeuthe three circuits. That is, that the four mutual inductances between the four line windings neutralize one another. To provide thatthe effective mutual inductance between the circuits be zero, two of.

the four mutual inductances must balance In the arrangements f described, the resultant disposition of the .specific `toroidal magnetic cores, such `as claimed .they are also balanced electrostaticallyand with respect to effective resistance and self inductance. In consequence of this, there will be theoretically no crosstalk between the several circuits of the loading unit.

The division of line windings of a branch magnetic circuit loading coil into separate sections, and the distribution of said sections upon the associated core, as illustrated for not aimed herein, but relates to a diii'erent invention claimed in my copending application Serial No. '55,716, iiled October 13, 1915, renewed June 14, 1917, Serial No. 174,778. The structure herein illustrated and'describe'd also constitutes another embodimentof another different invention claimed in my copending application Serial No. 55,714, filed October 13, 1915. Another embodiment of interconnected herein, is disclosed in my said copending application 'Serial N0. 55,716 (renewal Sr.

I-claim:

V 1. The combinationV with two physical circuits consisting of line conductors together furnishing a phantom circuit, of an gramplein Fig. 2 of the drawings, is

in'ductance device comprising a magnetic core having two separated portions each forming a closed figure and intermediate portions, and a winding for each line conductor situated upon the core, the windings being positioned to produce a magnetic flux in the core passing through both the firstnamed portions and interml `liate iortions on passage of either side circuit or phantom circuit current.

2. The combination with two physical cir- -cuits'consisting of line conductors together furnishing a phantom circuit, of an inductance device comprising a magnetic core having two separated portions each forming a closed figure and intermediate portions, a winding for each line conductor situated upon the intermediate portions of the core, the windings for each phi ical y:ircuit being connected with their inductances mutually aiding for side circuit current, and the .vin

ings of the two physical circuits being connected with their inductances mutually aiding for phantom circuit current.

3. The combination with two physical cuits consisting oi' lino conductors togeiiioi?.

:iumishing a phmiiom oii'ouii, of im, inimfr mines device comprising .a magnetic oom having" two Sopai'mefi por'tiom iiomi ing a. dosed figure vinci symmetiricaiiy im ranged. intermediate poi'tions, ami ai wind ing fof each line conductor situated upon the inteimediate portions of the com.

5. The combination with l@Wo physical-ciw cuiis consisting of ii'ne conductors together furnishing a. phantom. circuit7 of an induc- 'i-anco devine comprising a, -mag'netio core having two separated portions each forming a. closed figure amd intermediate portions symmotricaiiy arianged'in opposite pairs? and windings for-each pair of lino .confino-- tors situteci. rfapectiveiy upon such Oppem site pairs of core porioiis.

6. An' inductance doi/io@ compacisiiig; .a magnetic core having opposite and minous ,anni intm'medifito poriono, and in notano@ (gli 'portions oomieomig tho ioioidss7 :md Wimi:

i''o'f ii pimjaliiy of talking oicxiiiss oomiioci to iii@ commuting porwions., smid windboiiismdaped when avoui'reni; nosed iu @no oi. saiii oiioiiigs to produ@ inolum'ivo ofi'ooas in l Alumi rho said ciouim loading-omi comprising two toioicis lying in paraiiei planes: and fom' connecting portions oquaiiy spaced about the toroids, and iin@ windings :for in plurality 0i 'talking eircuits coniiied to the commuting portions, said windings, being adapted when :iJ current is; passed in omI of Said circuits ilo pi'ofiuce inductive effects individual to said circuit.

In testimony iwimreeoi,v I have signed my name to. thio specification in'- the presence of two subscribing 'wimesses, this 527th day of Sopomiao 1.9151

LLOYD ESPENSCHEEU.

ii/'itnossesz (JHM. Gn Hiixsriiz, Jr., EL C; FRANC@ 

